Crystal Field Theory

Given structure [Co(H₂O)₆]²⁺.

What type of orbital of this complex?

• Inner octahedron orbital complex

• Outer octahedron orbital complex

Given structure [Co(H₂O)₆]²⁺.

Find the hybridisation of the complex.

• Sp³d²

• d²sp³

• Sp³

• dsp²

Given structure [Co(H₂O)₆]²⁺.

Find the magnetic moment for Co²⁺ (high and lower spin).

• 3.87 and 1.73

• 2.98 and 1.65

• 3.56 and 1.49

• 3.45 and 1.24

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which complexe has the following geometry?

• [FeBr₄]^2-

• [NiCl₄]^2-

• [Zn(NH₃)₄]²⁺

• [Ni(CN)₄]^2-

Tags

NGSS.HS-PS1-3

Why in octahedral complexes used term t_2g and e_g whereas tetrahedral used term t₂ and e?

• Tetrahedral has centre of symmetry.

• Octahedral does not have centre of symmetry

• Octahedral has centre of symmetry.

Light is absorbed in range from 560nm – 590nm. Given the average wavelength is 580nm. Calculate the crystal field splitting energy, Δ_CFSE and determine the colour observed.

• 256 J/mol, violet colour

• 206 kJ/mol, violet colour.

• 260 kJ/mol, yellow colour

• 216 kJ/mol, yellow colour

Tags

NGSS.HS-PS4-1

Given [Ni(H₂O)₆]²⁺ (high spin). Calculate Δ_CFSE and give configuration in term of t_2g and e_g.

• 2.6 Δ_0, t_2g¹e_g

• 1.2 Δ₀, t_2g⁶e_g²

• 1.2 Δ_t, t_2g⁶e_g²

• 2.6 Δ_sp, t_2g⁵e_g²

The following are the advantages of CFT except

• Assume all five d orbitals having the same energy.

• Able to explain colour formation.

• Produced a spectrochemical series.

• Able to estimate stability of the complex based on magnitude of Δ₀.

The weakness of CFT are

i) Fails to explain how arrangement of electron configuration in d-orbital.

ii) Fails to explain why the F^- ion has very ionic property

III) Fails to explain why the CN^- and CO give very high ligand field effect with all metal.

Iv) Fails to estimate relative stability among complexes by using E_CFSE.

• All of the above.

• I and III

• I, II and III

• II and III

What is the difference between VBT and CFT?

• VBT stands for Valence Bond Term and CFT stands for Complex Field Theory

• VBT explains about formation of colour while CFT explains about the variation in magnetic moments.

• VBT explains the mixing of orbitals whereas CFT explains the splitting of orbitals.

• CFT explains the mixing of orbitals meanwhile VBT explains the mixing of orbitals.